Shop online from retailers that specialize in movie posters like MoviePoster.com. These sites often feature a number of different pay-per-view posters from past WWE events. However, read the fine print carefully since some of their posters, especially the older ones, are actually reproductions.
Search auction sites like ebay for new, used and reproduction pay-per-view posters. There are a variety of sellers offering their merchandise on ebay and there are many sellers who specialize in wrestling memorabilia. If you’re looking for vintage posters or originals ebay is often the best place to look.
Call you local cable provider and ask about posters for recent or future events. Often the cable company has posters in their office to advertise the event and to get people excited about it. Once the event passes they may throw out the posters to clear the space. Ask if there’s any way you can buy a poster from the event.
Keep an eye out for stores in your area that may have the posters up in their window. In some cases stores help sponsor the pay-per-view events and get free posters for advertising purposes. Talk to a store manager about the posters and ask if there’s any way you can have one after the event.